In response to the development of electronic control technologies, it is the rapidly-growing trend to electronically control engines. Fuel injection methods using a common rail are being widely applied to electronically controlled engines since fuel injection can be performed under high pressure even with a low load and can be easily performed in response to a control signal.
A variety of research and development is being performed on electronically controlled fuel injection valves that are key devices of common rail fuel injection systems. In order to improve the performance of the fuel injection valve, a large number of patent applications are being filed for various types of fuel injection valve driving mechanisms.
A traditional mechanical fuel injection valve is configured such that fuel is injected by lifting up a needle using only the pressure of fuel that is fed into a chamber of a nozzle part. Since injection characteristics such as the time to inject fuel and the amount of fuel to be injected are always uniform, control over fuel injection cannot be performed independently from the operating condition of an engine and this can be problematic.
In addition, in the case of a traditional electronically controlled fuel injection valve, fuel is constantly supplied to the nozzle part through a fuel supply port and the nozzle part is constantly subjected to high pressure. Consequently, a large amount of fuel leaks into the combustion chamber when accidents, such as damage to the needle of the nozzle or to a valve seat, occur.